I don't know if it's too late, but hearing some quotes from Gamespot's video leaves the quality of writing to be less than desired. From around the 6:40 mark we hear Swen mention that due to the neccessity of the box and its connection to Shadowheart there will be moments where things won't make sense story wise such as her showing up just in time for the macguffin. The solution I would think of is to separate the box from her at the very start, just make it so that instead of her having the box creating all these problems, make it so that she's actively looking for the box. That way she still has some sort of connection and the box can be placed to where the player can freely take it where it'd make sense.
I can't comment on how feasable it would be to remove Shadowheart from having the box without knowing more of her arc - as far as I know she is meant to have the box, as long as player wants to adventure with her.
